Polymer materials having in the molecule thereof a carbon-carbon double bond, such as EPDM, NR, and NBR are easily degraded by a solar light (particularly ultraviolet ray) or ozone, which may adversely affect the weatherability depending on the application of the materials. Such polymer materials may dissolve in a specific organic solvent or the like, so the materials cannot be applied to a part that may be contacted with the organic solvent or the like. Therefore, as one measure for enlarging the application of such polymer materials, a modification (chemical modification) with a nitrile oxide is considered.
For example, Patent Literature 1 describes a technology for enhancing the dispersibility and the reactivity of a filler such as carbon black, and the like by subjecting natural rubber or synthetic diene-based rubber together with 4-(2-oxazolyl)-phenyl-nitrile oxide or 4-(2-thiazolyl)-phenyl-nitrile oxide to a stirring treatment or a kneading treatment to modify the natural rubber or the like.
However, when a polymer material such as EPDM, NR, and NBR has been modified with a nitrile oxide, the number of carbon-carbon double bonds in the molecule decreases, and depending on the case, the double bonds are lost, and therefore, the crosslinking reaction with sulfur or the like may not be performed.
Patent Literature 2 describes a technology for crosslinking a diene-based elastomer with a bifunctional nitrile oxide such as mesitylene dinitrile oxide (MDNO). However, such bifunctional nitrile oxide has extremely high reactivity, so needs to be kneaded and processed at a relatively low temperature, and thus has poor processing characteristics.